No Coil Spark

[Rick]

Hey guys, as you know I’ve just finished my engine rebuild and was ready to start it up this weekend after putting it back in the car but I have a problem.

I’m not getting any spark out of the coil. 

I have not rewired the car yet so the only wires I have are from the battery to the starter and to the coil and from the distributor to the coil.

I’ve tested the coil with a meter and it looks fine.  I’ve verified that the problem is BEFORE the distributor.

I think I may have a ground issue but I’m still checking into that.

Any thoughts?

[Royal]

Rocky, The ignition circuitry on these cars is quite simple.  There is a hot lead (positive) run directly to the coil.  It is always hot (if the ignition is on).  The other side of the coil goes to the points.  When the points are closed, current flows through the coil to the ground that is through the points.  As a cam lobe opens the points, the current through the coil is interrupted.  Coils don’t like that and they generate large electrical voltage that is sent through the big wire to center of the distributor cap.  As the rotor goes around it decides which spark plug to fire depending on which direction it is pointing. 

The easiest thing is to just use jumper wire from the hot of the battery directly to the coil.  Also make sure that you have the engine grounded well.  (ps you can not necessarily prove a coil to be good with a volt-ohmmeter.  Some faults will show themselves, others will not.)

[Rick]

Roy,

I appreciate your narrative but this is all stuff I already knew…and did.

I’m trying to figure out the best way to ground a new coil on an old engine.  Any thoughts on this?

[Royal]

Mine is just mounted and grounded by a bolt onto the fan shroud at about the 10 o’clock position looking forward.  I think that this is rather normal. 

[newkitman]

Rocky,

If you’re sure its before the coil, then you probably have a bad or loose ground. Check the ground strap between frame and the engine. Sometimes that nut comes loose a bit. And check the bolts securing the coil to the fan shroud. I’d go over again and make sure all the grounds are tight and all the terminals on the coil are tight. And make certain the wire terminal connected to the points is not touching the inside of the coil. I did that once and it drove me nuts until my son found it. Just my .02 worth. Let us know what you find out.

Allen Caron
VW based 53MGTD - "MoneyPenny"
"If one thing matters, everything matters" - from the book The Shack

[Scott A Chynoweth]

The coil should ground internally through the points. Go back to basics.Ground engine to battery.Hot lead to starter,run a HOT wire to the coil from the battery.should fire.DOUBLE check your conections on the coil.VW runs a 1 and 15 not a + – get the right hook up – should go to the dizzy.and + to the battery.Just pull the hot lead from the coil to shut her down,or a simple in line switch.

[Author]

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